robocopy

This tutorial describes how to use robocopy to copy all files and folders from a source to a destination. With the same command, you can run it again later, and it will only copy files that have changed to the destination. Also, if files were deleted from the source, it will remove them from the destination as well. This command will also keep all of the NTFS permissions and file attributes.

A typical use scenario for this command is copying a large file share. You can run the command once to copy the bulk amount of the data, then you can run it again later, and it will only copy changed files, which will make it much faster.